Three prime untranslated region
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The three prime untranslated region (3' UTR) is a particular section of messenger RNA (mRNA). It follows the coding region.
An mRNA codes for a protein through translation. The mRNA also contains regions that are not translated. In eukaryotes the cap, 5' untranslated region, 3' untranslated region, and polyA tail (see diagram).
In prokaryotes mRNA structures have some differences (see mRNA) as do histone mRNAs. However, both have 3' UTRs.
Several regulatory sequences are found in the 3' UTR:
- A polyadenylation signal, usually AAUAAA, or a slight variant. This marks the site of cleavage of the transcript approximately 30 base pairs past the signal, followed by the addition of several hundred adenine residues (poly-A tail).
- Binding sites for proteins, that may effect the mRNAs stability or location in the cell, for example the SECIS elements, which occurs in the 3' UTRs of a small number of eukaryotic mRNAs, direct the ribosome to translate some UGA as selenocysteines rather than stop codons, an extension of the genetic code.
- Binding sites for miRNAs a type of RNAi.
[edit] References
[1] Translational control by the 3'-UTR: the ends specify the means. Trends Biochem Sci 2003, 28:91-98
[edit] External links
[2] UTResource
[3] RNAMotifs
[4] Medical Subject Heading: 3' Untranslated Regions
